The invention pertains to rocket launchers which are used for shipping, storing, and air firing of rockets whereby radiation, static or stray voltage may be encountered which is sufficient to cause premature firing of the rockets therein. To counteract this hazard, many systems have been devised to ground the firing squibs on the rockets until it is time for the rockets to be fired.
Assignee's two prior applications, referenced above, disclose firing circuitry incorporating such safety devices. Although these devices operated satisfactorily for their purpose the search for a system of greater safety goes on.
According to the present invention, all of the rocket firing circuits are grounded through a separate contact in an oscillatory grounding switch which removes the ground only when full current is applied to a solenoid operator. Oscillatory movement of the grounding switch causes step by step rotary motion of the rocket firing switch to apply current serially to the rockets in a predetermined sequence. Current is applied to the firing or stepping switch, however, only during the final instant just as the contacts are closed in the stepping switch. This is accomplished by a spring biased switch which is allowed to close by a cam surface, for example, fixed to the oscillatory switch.